Yes you can. Technically, adding pH Up (sodium carbonate / washing soda) is identical to adding Alkalinity Up (sodium bicarbonate / baking soda) plus Lye (sodium hydroxide / caustic soda) and the lye is similar to Borax. So after you figure out how much of each you would need, you can see which would be cheaper. Usually in this situation I just use pH Up, but that's just for convenience. By the way, Arm & Hammer Super Washing Soda (that says in the ingredients it's Sodium Carbonate and is NOT the laundry detergent) is the same as pH Up.